Cooking liquor



?atented Apr. 1, i924.

JWREIH E. PLUMSTEAD, 0F WILMINGTON, DELAWARE, ASSIGNOR TO THE JESSUP & MOORE PAPER 00., OF PHILADELPHIA, PENNYLVANIA, A. CORI'QRATIQN OF MASSACHUSETTS.

No Drawing. original application filed April 18, 1923, Serial No.. 632,927, Divided and this application filed January 18, 1924. Serial napsmss. I

To all whom it may concern Be it known that I, J osnrn E. PLUMsrnAn, a citizen of the United States, and resident of Wilmington, in the county of New Castle and State of Delaware, have invented certain new and useful Ini rovements in Cooking Liquors, of which t e following is a speci- 'fication.

This invention relates to an alkaline cooking liquor for the production of chemical pul as used in paper making.

l he principal object is the provision of such a liquor which will contain sulphur in such a form that the lignious or other acids of the wood will not cause the fOrmation. of compounds containing sulphur which will readily be decomposed; This difficulty has long beena problem, as it is know that the "presence of sulphur. has a desirable .t eaction upon the pulp, but the difficulty has been in placing the sulphur in the liquor in such form that it was not lost at one or more points in the cycle.

I have described in my co-pending application No. 632,927, filed April 18, 1923, of which this is a division, one method of'introduc-ing sulphur intothe cycle as operated under the so-called soda prochss, which sulphur finds its way ,into the cooking liquor in such a form that the minimum. amount of this I element is lost in the cooking and other steps.

I have found, however, upon chemical analysis of the liquor produced by ca-rryingout the method described in my above mentioned application, that sodium thiosulphate,; and sometimes sodium sulphite, are present, together with the usual sodium hydroxides cocaine LIQUOR.

produced in the causticizing ste 'whe1*e lime is added to the black ash eachings which contain sodium carbonate. I attribute the beneficial results obtained to the presence of these compounds. It will thus be apparent that a liquor may be prepared and these compounds as such, added thereto before the cooking or digest-ion takes place.

The exact amount of the sulphur salts mentioned tobe added will have to be determinedby the one skilled in the art who is to employ the same, for the reason that the proportions vary between Wide limits and are dependent on the type of raw material used, the water content, the pressure and concentration obtained in the digestion, and other well known conditions. However, it is noted that only small amounts of sulphur need be added upon completion of any cycle, which deficiency may be determined accurately at any one of various points in the cycle, by anal sis.

It may be ound desirable to utilize salts of other metals of the alkali group in the cooking liquor, although the particular method mentioned forms salts which are desirable because of cheapness. Having thus described my invention, what I claim is-:-- v

1. In the preparation of chemical pulp, the use of a cooking liquor comprising sodium hydroxide and sodium thiosulphate.

2.'In the preparation of chemical pulp, the use of areooking liquor comp-rising a hydroxide and'n thiosulp-hate.-

In testimon whereof I aflix m signature.

- J SEPH E; PLU STEAD. 

